Hyaluronan-Inorganic Nanohybrid Materials for Biomedical Applications

Nanomaterials, including gold, silver, and magnetic nanoparticles, carbon, and mesoporous materials, possess unique physiochemical and biological properties, thus offering promising applications in biomedicine, such as in drug delivery, biosensing, molecular imaging, and therapy. Recent advances in nanotechnology have improved the features and properties of nanomaterials. However, these nanomaterials are potentially cytotoxic and demonstrate a lack of cell-specific function. Thus, they have been functionalized with various polymers, especially polysaccharides, to reduce toxicity and improve biocompatibility and stability under physiological conditions. In particular, nanomaterials have been widely functionalized with hyaluronan (HA) to enhance their distribution in specific cells and tissues. This review highlights the most recent advances on HA-functionalized nanomaterials for biotechnological and biomedical applications, as nanocarriers in drug delivery, contrast agents in molecular imaging, and diagnostic agents in cancer therapy. A critical evaluation of barriers affecting the use of HA-functionalized nanomaterials is also discussed, and insights into the outlook of the field are explored.

Co3O4 nanoparticles/cellulose nanowhiskers-derived amorphous carbon nanoneedles: sustainable materials for supercapacitors and oxygen reduction electrocatalysis

Amorphous carbon nanoneedles-supported Co₃O₄ nanoparticles, materials that have electrocatalytic activity for ORR and the ability to store charges, are synthesized with nanoreactors using Co(ii) ions and cellulose nanowhiskers as precursor.

Reduced graphene oxide and graphene composite materials for improved gas sensing at low temperature

Reduced graphene oxide (rGO) was investigated as a material for use in chemiresistive gas sensors. The carbon nanomaterial was transferred onto a silicon wafer with interdigital gold electrodes. Spin coating turned out to be the most reliable transfer technique, resulting in consistent rGO layers of reproducible quality. Fast changes in the electrical resistance at a low operating temperature of 85 °C could be detected for the gases NO₂, CH₄ and H₂. Especially upon adsorption of NO₂ the high signal changes allowed a minimum detection of 0.3 ppm (S/N = 3). To overcome the poor selectivity, rGO was chemically functionalized with octadecylamine, or modified by doping with metal nanoparticles such as Pd and Pt, and also metal oxides such as MnO₂, and TiO₂. The different response patterns for six different materials allowed the discrimination of all of the test gases by pattern recognition based on principal component analysis.